tbuckley/cabot-search huggingface dataset:
OS06.6.A FLAIR-SIGNAL INTENSITY CHANGE AS A PREDICTOR OF PROGRESSIVE GLIOBLASTOMA IN THE EORTC CENTRIC AND CORE STUDIES
Authors: C M Flies, M Friedrich, P Lohmann, K van Garderen, M Smits, J C Tonn, M Weller, N N Gatson, N Galldiks, T J Snijders
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND In patients with glioblastoma, radiological recurrence of enhancing tissue after chemoradiotherapy can originate from progressive disease (PD) or pseudoprogression/treatment-associated changes. In earlier studies, a change of the FLAIR-signal intensity (SI) predicted PD with 18-84% sensitivity and 71-100% specificity, both with quantitative resection cavity to ventricle SI ratio of 7.3. We assessed the rate of FLAIR-signal intensity change in patients with O6-methylguanine DNA methyltransferase (MGMT) promoter-methylated or -unmethylated glioblastoma from the randomised CENTRIC and CORE studies (NCT00689221, NCT00813943). These patients were treated with chemoradiotherapy or chemoradiotherapy with cilengitide, an integrin inhibitor. METHODS Patients from both studies with a gross total resection and ≥3 follow-up MRIs were included. The outcome was determined by the modified RANO criteria of 2017. Two researchers evaluated the FLAIR-SI of the resection cavity. A positive SI change was scored qualitatively in case of a visually brighter signal intensity than on the previous MRI. Quantitative analysis was based on a ratio of SI in the resection cavity compared to SI of the ventricles. RESULTS Follow-up was available for 307 patients. Median time from RT to (preliminary) progressive disease was 6.2 months for MGMT promoter-methylated (interquartile range, (iqr)=2.5-14.7) and 6.0 for MGMT promoter-unmethylated glioblastoma (iqr=2.7-8.9). Of the 307 patients, 142 patients showed stable disease, response, or treatment-associated changes and 165 (preliminary) PD at the end of follow-up. A qualitative FLAIR-SI change was found in 61 patients (19.9%) and 44 of these developed (preliminary) PD, with a positive predictive value of 72.1% (95%-CI 59.2-82.9%); positive predictive value was 88.9% for MGMT promoter-unmethylated and 67.4% for MGMT promoter-methylated glioblastoma. We found an overall sensitivity of the FLAIR-SI-change for PD of 26.7% (95%-CI 20.1-34.1%), with ranges of 22.9 to 39.2% depending on MGMT promoter methylation status and treatment allocation; specificity ranged from 88 to 91.3%, with an overall specificity of 88.0% (95%-CI 81.5-92.9%). Median time from first FLAIR-SI to progression was 0 months (iqr=0-2.7) with a range of 0 to 13, and from the brightest signal was 0 months (iqr=0-1.0). The average signal intensity ratio was 10.2 at the time of the brightest signal; further quantitative analyses will be presented. CONCLUSION We confirmed the positive predictive value of a change in FLAIR-signal intensity of the resection cavity for concurrent or subsequent progressive disease in resected glioblastoma. Patients with such a change of the signal intensity should be worked up further on (e.g. PET imaging, biopsy, any clinical change) or else undergo another MRI closely.
OS09.5.A BREAKING DOWN BARRIERS: THE IMPACT OF BLOOD-BRAIN BARRIER DISRUPTION ON THE GLIOMA METABOLIC MICROENVIRONMENT, IN SITU
Authors: C Riviere-Cazaux, L Carlstrom, K Rajani, A Munoz-Casabella, M Rahman, A Gharibi-Loron, D Brown, K Miller, J White, B Himes, I Jusue-Torres, S Ikram, S Ransom, R Hirte, J Oh, W Elmquist, J Sarkaria, R Vaubel, M Rodriguez, A Warrington, S Kizilbash, T Burns
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND The microenvironment of glioblastoma is complex and defined in part by protumorigenic metabolic changes. Within this microenvironment, blood-brain barrier disruption is often associated with the most aggressive portions of the tumor. To date, the metabolic tumor microenvironments of enhancing, blood-brain barrier (BBB) disrupted portions of gliomas, as compared to BBB-intact tumor, remain poorly understood. Specifically, it is unclear if the associated blood-brain barrier disruption merely reflects or functionally supports tumor aggressiveness. METHODS Intra-operative high-molecular weight microdialysis was utilized under an investigational device exemption (NCT NCT04047264) to sample the extracellular metabolome of radiographically diverse regions during fifteen neurosurgical resections. The global extracellular metabolome of recovered microdialysate from contrast-enhancing and non-enhancing tumor, as well as brain adjacent to tumor, was evaluated via ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) on the Metabolon platform and assessed using enrichment and correlation analyses. RESULTS Among 162 named metabolites identified via ultra-performance liquid chromatography tandem mass spectrometry, a novel glioma-associated metabolite, guanidinoacetate (GAA), was 126.32x higher in enhancing tumor than in adjacent brain and 13.63x higher in non-enhancing tumor than brain. Forty-eight additional metabolites were 2.05-10.18x more abundant in enhancing tumor than brain, including carnitine family members and all nine large neutral amino acids. Except for GAA and 2-hydroxyglutarate in IDH-mutant gliomas, differences between non-enhancing tumor and brain microdialysate were comparatively modest and less consistent, suggesting heterogeneity in the glioma metabolic microenvironment of blood-brain barrier (BBB) intact areas as compared to BBB-disrupted portions of gliomas. Interestingly, the enhancing but not the non-enhancing glioma metabolome was significantly enriched for plasma-associated metabolites, largely comprising amino acids and carnitines. CONCLUSION Our patient-derived data suggest that the BBB-disrupted metabolome of high-grade gliomas is characterized by metabolite diffusion from circulation into the tumor microenvironment. Further studies are ongoing to determine how this alteration in the glioma extracellular metabolome impacts glioma behavior and how it could be therapeutically targeted via BBB-modulating drugs.
P13.02.A APPLICATION OF NOVEL PACS-BASED INFORMATICS PLATFORM TO IDENTIFY IMAGING BASED PREDICTORS OF CDKN2A ALLELIC STATUS IN GLIOBLASTOMAS
Authors: N J Tillmanns, J Lost, J Tabor, S Vasandani, S Vetsa, N Marianayagam, K Yalcin, Z Erson-Omay, M von Reppert, L Jekel, S Merkaj, D Ramakrishnan, A Avesta, I Dixe de Oliveira Santo, L Jin, A Huttner, K Bousabarah, I Ikuta, M Lin, S Aneja, B Turowski, M Aboian, J Moliterno
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND Gliomas with CDKN2A mutations are known to have worse prognosis but imaging features of these gliomas are unknown. Our goal is to identify CDKN2A specific qualitative imaging biomarkers in glioblastomas using a new informatics workflow that enables rapid analysis of qualitative imaging features with Visually AcceSAble Rembrandtr Images (VASARI) for large datasets in PACS. Gliomas with CDKN2A mutations are known to have worse prognosis but imaging features of these gliomas are unknown. Our goal is to identify CDKN2A specific qualitative imaging biomarkers in glioblastomas using a new informatics workflow that enables rapid analysis of qualitative imaging features withVisually AcceSAble Rembrandtr Images (VASARI) for large datasets in PACS. MATERIAL AND METHODS Sixty nine patients undergoing GBM resection with CDKN2A status determined by whole-exome sequencing were included. GBMs on magnetic resonance images were automatically 3D segmented using deep learning algorithmsincorporated within PACS. VASARI features were assessed using FHIR forms integrated within PACS. RESULTS GBMs without CDKN2A alterations were significantly larger (64% vs. 30%, p=0.007) compared to tumors with homozygous deletion (HOMDEL) and heterozygous loss (HETLOSS). Lesions larger than 8 cm were four times more likely to have no CDKN2A alteration (OR: 4.3; 95% CI:1.5-12.1; p&amp;lt;0.001). The pial invasion was predictive of HOMDEL (OR: 8.1, 95% CI: 1.8-53.2; p&amp;lt;0.012) as tumors with pial invasion were eight times more likely to be HOMDEL, even after adjusting for deep white matter and subependymal invasion. CONCLUSION We developed a novel integrated PACS informatics platform for the assessment of GBM molecular subtypes and show that tumors with HOMDEL are more likely to have radiographic evidence of pial invasion and less likely to have deep white matter invasion or subependymal invasion. These imaging features may allow noninvasive identification of CDKN2A allele status.
OS01.5.A THE USE OF MULTIOMICS IN THE IDENTIFICATION AND CHARACTERISATION OF TERTIARY LYMPHOID STRUCTURES IN GLIAL TUMORS
Authors: J H Lun, A Singh, P Cakmak, M Köhler, J Schupp, J Macas, K H Plate, Y Reiss, K Imkeller
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND Tertiary Lymphoid Structures (TLSs) are organized immune cell aggregates present in non-lymphoid tissues for the initiation and maintenance of local and systemic anti-tumor immune response. The presence of TLS has been associated with better prognosis and clinical outcome in several cancer types, including lung and melanoma. However, the formation of TLS and its potential role in intra-tumoral immune response remains unclear. TLS are particularly interesting in gliomas as tumor-infiltrating lymphocytes is inefficient possibly due to the immunosuppressive microenvironment and the presence of the blood brain barrier. This study aims to identify and characterize the presence of TLS in glioma patients, to understand its role in generating a local immune response against tumors and identify potential biomarkers. We characterized TLS in glioma by immunohistochemistry, RNA sequencing from TLS positive tumors and used spatial transcriptomics to map TLS gene expression within the tumors. MATERIAL AND METHODS Of the 1274 adult patients with diffuse glioma, resected between 2015 and 2021, a total of 663 FFPE-tissue samples were available for B cell infiltration IHC-screening. Subsequently, the TLS+ samples were characterized using spatial transcriptomics and Opal-TSA mIHC, a spatial proteomic method that enables a simultaneous detection of 6 antigens in FFPE tumor tissues. A selection of TLS+ and matched TLS- tumors were subjected to bulk-tissue whole RNA sequencing. Downstream analysis such as cell-type specific transcriptional deconvolution and differential gene expression were performed. Furthermore, a multimodal analysis of TLS in glioma was conducted by combining the genomic, transcriptomic, spatial proteomics and clinical data. RESULTS B cell accumulations were observed in 13.1% of all gliomas. Small CD20 B cells accumulation, named perivascular immune cells (PVIC), and TLS were observed in 10.7% and 2.4%, respectively. We investigated the overall survival of patients in the TLS+, TLS- and PVIC groups. So far, no significant differences were observed. The transcriptomic analyses of TLS+ with TLS- tumors revealed an upregulation of genes related to innate and adaptive immune responses, complement cascade and the extracellular matrix. Genes associated with neural differentiation were expressed higher in TLS- compared to TLS+ tumors. Moreover, our multimodal analysis revealed the presence of distinct classes of TLS in glioma which differed in their cellular and molecular compositions. CONCLUSION Using a multimodal analysis, this study identified B cell accumulation and TLS in glioma patients. In contrast to other cancer types, the presence of TLS in glioma did not correlate with a higher overall survival. However, the role of TLS in glioma and their prognostic and therapeutic relevance remains under investigation with further analyses currently underway.
P02.24.B A DRUG DISCOVERY PLATFORM FOR COMBINATORIAL TARGETING OF CELL STATES AND ENTITIES
Authors: B Jiang, M Schmitt, G Gargiulo
Journal: Neuro-Oncology (2023)

Abstract Glioblastoma (GBM) is a lethal brain tumor with limited therapeutic options. Therapeutic resistance arises from the collaboration among heterogeneous and highly plastic cellular entities and states conserved across GBM patients and the tumor microenvironment.Tumor cells adapt in response to the current standard of care and infiltration of innate immune cells, recurrently acquiring a mesenchymal state that drives therapeutic resistance.Moreover, the blood-brain barrier (BBB) poses challenges to the effectiveness and bioavailability of approved therapeutics, as well as the discovery of new ones.Our lab has developed synthetic locus control regions (sLCRs) as transcriptional reporters for glioblastoma subtypes, enabling the study of cell identity and state transitions in vitro and in vivo. We have combined this tool with validated cellular models for glioblastoma mesenchymal transition and therapeutic resistance to establish an in vitro phenotypic screening platform. Currently, we are utilizing this platform to identify treatment combinations and dosing schemes that aim to overcome innate immunity-driven resistance and synergize with the standard of care. As a proof-of-concept for a new generation of brain tumor target discovery platforms, we will present the setup of our platform and preliminary results for a class of BBB-penetrant drugs.
P14.09.B IS BLOOD-DERIVED EXOSOMAL HTERT TRANSCRIPT A MARKER OF ONCOGENIC ACTIVITY IN PRIMARY BRAIN TUMORS? AN EXPLORATORY STUDY
Authors: O Uziel, A Kanner, E Beery, S Lev, M Lahav, S Horn-Fichman, S Har Nof, Y Laviv, S Yust Katz, A Amiel, A Levi-Barda, P Raanani, Y Sela, Z Cohen, T Siegal
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND In order to proliferate indefinitely, all tumors require a telomere maintenance mechanism. The expression of human telomerase reverse transcriptase (hTERT) enables telomere maintenance and provides cancer cells with limitless replicative potential. As such, it may serve as an attractive biomarker for oncogenic activity. This study explored whether a liquid biopsy that analyses blood derived exosomal hTERT transcript (e-hTERT-trans) may serve as such a biomarker in gliomas and meningiomas when compared to healthy controls. MATERIAL AND METHODS Exosomes were isolated from the pre-operative sera of patients’ samples stored in the biobank of both Rabin and Sheba Medical Centers. The levels of e-hTERT-trans were measured in 81 healthy controls, 117 meningiomas, 17 low-grade gliomas, and 61 glioblastomas. Clinical parameters of the patients were collected retrospectively and compared to the levels of the e- hTERT-trans. RESULTS The Upper normal limit of controls e-hTERT-trans was 1.85 relative quantitation (RQ). The rate of detection increased with rising tumor grade and correlated with tumor recurrence in meningiomas: mean RQ without recurrence (2.17+11.7) vs. with recurrence (3.59+4.42; p=0.002). In glioblastomas, pre-operative measurements correlated with tumor volume and with the disease course on serial sampling. CONCLUSION We demonstrated for the first time that the expression of e-hTERT-trans transcript can be measured in the serum of primary brain tumors. This exosomal marker carries the potential to serve as a biomarker once used in conjunction with other clinical and radiological parameters. Future studies are required to investigate whether the sensitivity could be augmented and whether it can be implemented into routine patients care.
P05.01.B PROGNOSTIC MARKERS OF DNA METHYLATION AND NGS SEQUENCING IN PROGRESSIVE GLIOBLASTOMA FROM THE EORTC-26101 TRIAL
Authors: T Kessler, D Schrimpf, L Doerner, L Hai, L Kaulen, J Ito, M van den Bent, M Taphoorn, A A Brandes, A Idbaih, J Domont, P M Clement, M Campone, M Bendszus, A von Deimling, F Sahm, M Platten, W Wick, A Wick
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND The EORTC-26101 study was a randomized phase 2 and 3 clinical trial of bevacizumab in combination with lomustine versus lomustine alone in progressive glioblastoma. Other than for progression-free survival (PFS), there was no benefit from addition of bevacizumab for overall survival (OS). However, molecular data allows for the rare opportunity to assess prognostic biomarkers from primary surgery for their impact in progressive glioblastoma. MATERIAL AND METHODS We analyzed DNA methylation array data and panel sequencing from 170 genes of 380 tumor samples of the EORTC-26101 study. These patients were comparable to the overall study cohort in regards of baseline characteristics, study treatment and survival. RESULTS 295/380 (78%) of patients’ samples were classified into one of the main glioblastoma groups receptor tyrosine kinase (RTK)1, RTK2 and mesenchymal. There were 10 patients (2.6%) with isocitrate dehydrogenase (IDH) mutant tumors in the biomarker cohort. Patients with RTK1 and RTK2 classified tumors had lower median OS compared to mesenchymal (7.6 vs. 9.2 vs. 10.5 months). O6-methylguanine DNA-methyltransferase (MGMT) promotor methylation was prognostic for PFS and OS. Neurofibromin (NF)1 mutations were predictive of response to bevacizumab treatment. CONCLUSION Thorough molecular classification is important for brain tumor clinical trial inclusion and evaluation. MGMT promoter methylation and RTK1 classifier assignment were prognostic in progressive glioblastoma. NF1 mutation may be a predictive biomarker for bevacizumab treatment.
P12.01.A TUMOR CELL SENESCENCE AND IMMUNE MICROENVIRONMENT IN GLIOBLASTOMAS
Authors: S Kim, T Roh, T Park, J Kim
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND Cellular senescence (CS) is a state of irreversible cell cycle arrest, and the expression of p16INK4a in cells is one of the reliable markers for CS. However, senescent cells are metabolically active with the senescence-associated secretory phenotype (SASP), which can influence the tissue microenvironment by paracrine signaling to the adjacent tumor, non-tumor, and immune cells. MATERIAL AND METHODS In the present study, we evaluated p16INK4a expression in glioblastoma and investigated its association with CS and SASPs. We analyzed the expression of p16INK4a in 73 glioblastomas by immunostaining. To examine the association of p16INK4a expression and CS, we performed senescence-associated β-galactosidase (SA-β-Gal) staining, a standard marker of CS, using glioblastoma cell lines and fresh frozen tumor tissues. For SASPs analysis, RNA sequencing with Gene Set Enrichment Analysis (GSEA) was performed. RESULTS Among 73 glioblastomas, twenty-eight cases (38.4%) revealed diffuse strong p16INK4a expression in tumor cells. The glioblastoma with diffuse p16INK4a expression (GMDP) patients were younger (52.4 vs. 59.2 years) and showed prolonged overall survival (median: 25.5 vs. 12.3 months) compared to those harboring negative expression. In vitro analysis, p16INK4a over-expressed glioblastoma cell line showed increased expression of SA-β-Gal which indicates CS. In addition, fresh frozen tissues from GMDP also revealed SA-β-Gal positivity. RNA sequencing analysis revealed that splicing or protein biosynthetic genes were enriched in GMDP, and GSEA showed significant enrichment of SASP genes (false discovery rate &amp;lt;0.05), especially chemokines associated with monocytes and macrophages. CONCLUSION Our data suggest that increased expression of p16INK4a in glioblastoma is associated with tumor cell senescence, and SASPs from senescent tumor cells could be one of the crucial modulators in the tumor immune microenvironment.
P12.09.B SMAC MIMETICS REPROGRAMS GLIOBLASTOMA IMMUNE LANDSCAPE AND POLARIZES MICROGLIA TOWARD A PRO-INFLAMMATORY ANTI-TUMORAL PHENOTYPE
Authors: E Snacel-Fazy, A Soubéran, C Colin, A Pagano, S Brustlein, M Grange, H Luche, C Siret, S Van De Pavert, F Debarbieux, G Rougon, D Figarella-Branger, E Tabouret, A Tchoghandjian
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND Glioblastomas are the most aggressive brain tumors in adult characterized by an immunosuppressive microenvironment. They are invaded by tumor-associated macrophages (TAMs) supporting tumor growth and treatment escape. One current therapeutic challenge is to restore an immunocompetent environment to improve treatment efficiency. A better knowledge of spatial distribution and function of TAMs is needed to design new promising therapeutic strategies. MATERIAL AND METHODS We used small molecules SMAC mimetics (SM) which are inhibitor of apoptosis (IAP) antagonists to decipher spatial distribution and function of TAMs. By using a syngeneic glioblastoma mouse model, we performed whole mount stainings and brain clearing to investigate immune cells quantity, and spatial organization within tumors and related to tumor vessels. We then performed molecular mass cytometry (CYTOF) to accurately phenotype the immune cells involved in SM response and gain functional data. We finally used human derived glioblastoma models (explants, immune cells sorting and tumoroids) to investigate the clinical relevance of our results. RESULTS Results showed that SM promoted immune cells CD45+ quantity and penetration within tumors including microglia. The treatment increased monocyte-derived dendritic cells, CD8EM T cells, reactive microglia while decreasing anti-inflammatory macrophages and basal microglia. Furthermore, SM treatment decreased contacts between microglia and CD8 T cells, and microglia PDL1+. Thanks to the use of human derived model, we found that CD14 is decreased upon SM treatment. By using TCGA databases, we found that low level of CD14 expression was correlated with a better prognosis. CONCLUSION SM reprogram glioblastoma immune landscape and modulate immune cell infiltration and organization within tumors. Furthermore, microglia is a key mediator in SM response. The targeting of CD14, IAP and microglia would be a promising therapeutic strategy.
P06.06.B PD-1 CHECKPOINT INHIBITION IN CONJUNCTION WITH NK-92/5.28.Z CELLS IS EFFECTIVE IN AN ADVANCED-STAGE GLIOBLASTOMA MOUSE MODEL AND INDUCES A CD4-ENRICHED T CELL RESPONSE
Authors: F Strassheimer, B Roller, I C Mildenberger, J Macas, T Alekseeva, T Tonn, L Sevenich, Y Reiss, K J Weber, K H Plate, A Weigert, W S Wels, J P Steinbach, M C Burger
Journal: Neuro-Oncology (2023)

Abstract INTRODUCTION Checkpoint inhibition in combination with adoptive cell therapy holds promise for cancer immunotherapy, and encouraging treatment responses have already been demonstrated for certain tumor types. Glioblastoma (GB) is the most common and aggressive primary brain tumor with limited efficacy of standard therapy. Analysis of the GB tumor immune microenvironment (TIME) has shown prominent immunosuppressive features, including upregulation of exhaustion markers on tumor and infiltrating immune cells. While the surrounding brain is HER2-negative, GB tumors are frequently HER2-positive, suggesting HER2 as a promising target for adoptive immunotherapy. Previous results from mouse glioma models showed efficacy of off-the-shelf NK-92/5.28.z CAR-NK cells targeted against HER2 as monotherapy in early stage tumors. RESULTS Combined treatment with NK-92/5.28.z cells and anti-PD-1 checkpoint blockade resulted in strong synergistic effects, with tumor regression and long-term survival observed even in advanced-stage tumor bearing mice. Analysis of tumor tissues using highplex methods (highplex multicolor flow cytometry, bulk RNAseq and multicolor IHC) revealed changes in lymphocyte infiltration and an altered TIME upon combination treatment with NK-92/5.28.z and anti-PD-1 checkpoint therapy. Specifically, infiltrating lymphocytes displayed an activated phenotype with predominance of CD4 cells and reduction of regulatory T cells. CONCLUSION Our data demonstrate that efficacy of HER2-specific NK-92/5.28.z cells can be enhanced by combination with checkpoint blockade. The combination therapy reverted the immunosuppressive TIME, resulting in successful treatment even of advanced othotopic tumors refractory to CAR-NK monotherapy. We are currently translating this concept into early clinical testing by including a respective patient cohort in our ongoing CAR2BRAIN phase I clinical trial (NCT03383978).